The invention relates generally to semiconductor device fabrication and, in particular, to device structures for a bipolar junction transistor, fabrication methods for a bipolar junction transistor, and design structures for a bipolar junction transistor.
Bipolar junction transistors include three terminals, namely an emitter, a base, and a collector, that comprise three distinct semiconductor regions. An NPN bipolar junction transistor includes two regions of n-type semiconductor material constituting the emitter and collector, and a region of p-type semiconductor material sandwiched between the two regions of n-type semiconductor material to constitute the base. A PNP bipolar junction transistor includes two regions of p-type semiconductor material constituting the emitter and collector, and a region of n-type semiconductor material sandwiched between two regions of p-type semiconductor material to constitute the base. Generally, the differing conductivity types of the emitter, base, and collector form a pair of p-n junctions, namely a collector-base junction and an emitter-base junction. A voltage applied across the emitter-base junction of a bipolar junction transistor controls the movement of charge carriers that produce charge flow between the collector and emitter regions of the bipolar junction transistor.
Bipolar junction transistors may be utilized in demanding types of integrated circuits, especially integrated circuits designed for high-frequency applications and high-power applications. Bipolar complementary metal-oxide-semiconductor (BiCMOS) integrated circuits combine bipolar junction transistors and complementary metal-oxide-semiconductor (CMOS) field effect transistors to take advantage of the positive characteristics of both transistor types in the integrated circuit construction.
Device structures, fabrication methods, and design structures are needed that improve the performance of bipolar junction transistors.